Inverse venturi meters have been used to measure very high flows. They are essentially a bulge in the tubular string with associated pressure taps as illustrated in U.S. Pat. No. 6,915,707 FIG. 6. FIG. 5 in that patent illustrates the classical shape of a standard venturi that tapers down to a throat dimension where one of the pressure taps is located while the other pressure tap is at an end of the venturi in the larger dimension. With the inverse flow meter there is also an end tap and one in the enlarged portion.
Well productivity varies with time and when a high producing well starts to trail off in production the measurement equipment designed for high flow ceases to be accurate or function at all primarily because there is no longer a sufficient differential pressure in an inverse venturi at the new and significantly lower flow rates. When that happened in the past the meter had to be pulled out and replaced by another meter to handle the lower flow rates. The replacement meter was frequently a standard venturi. Pulling out the production string and running in a new meter also takes time and has associated costs for running back in with the new meter but production that is interrupted and the risk of a lower rate when production is resumed due to the interruption in production for the replacement meter installation. These issues can also affect other types of installations where there is a dramatic change in flow rates that requires meter replacement in a subterranean location.
Venturi meters can also be located in surface lines for production or subsea. Venturi device are known to also be used as eductors to stimulate flow such as in gas lift applications. The present invention has application to the various applications for venturi devices regardless of their location and the manner in which the insert is deployed.
Venturi meters are generally described in USP and US Publication Numbers: U.S. Pat. Nos. 5,743,717; 5,128,052; 4,293,283; 6,015,018; 6,629,564; 2006/0131014; 2002/0029888. Also of interest is Canadian Application 2,297,003. Insert safety valves are run downhole into an existing housing to take over the function of another safety valve already downhole as illustrated in U.S. Pat. No. 4,660,647.
The present invention addresses the problem by running in an insert flow meter into an inverse venturi meter and securing it in position to use the taps from the initial meter. The insert meter is preferably a standard venturi that is rapidly deployed on wireline and latched into position in a manner that will direct all flow through its throat while having access to the taps of the original meter to take data or transmit signals in the way the original meter did it before. In a subsea application a remotely operated vehicle can be used to remove a pipe segment next to the venturi and insert the insert and reassemble. Surface installations can have the insert installed manually.
Those skilled in the art will gain a better understanding of the present invention from a review of the description of the preferred embodiment and the associated drawings that appear below with the understanding that the full scope of the invention is determined by the appended claims.